參考鏈接：https://www.cnblogs.com/yyxayz/p/4067529.html
示例代碼：

#include <iostream>
#include <algorithm>
#include <cstdio>
using namespace std;
const int maxn = 5000050;

// 快讀
inline int in()
{
    char ch;
    int a=0;
    while(!(((ch=getchar())>='0')&&(ch<='9')));  //利用getchar讀入，速度快。
    a*=10;a+=ch-'0';
    while(((ch=getchar())>='0')&&(ch<='9'))a*=10,a+=ch-'0';  //而後用ASCII碼轉為int 類型
    return a;
}

int n, a[maxn], b[maxn], nb = 0, c[maxn], nc = 0;

int main() {
    n = in();
    for (int i = 0; i < n; i ++) a[i] = in();
    int t = 0;
    for (int i = 0; i < n; i ++) t ^= a[i];
    int p = 1;
    while (!(t&p)) p <<= 1;
    for (int i = 0; i < n; i ++) {
        if (a[i] & p) b[nb++] = a[i];
        else c[nc++] = a[i];
    }
    int t1 = 0;
    for (int i = 0; i < nb; i ++)
        t1 ^= b[i];
    int t2 = 0;
    for (int i = 0; i < nc; i ++)
        t2 ^= c[i];
    if (t1 > t2) swap(t1, t2);
    printf("%d %d\n", t1, t2);
    return 0;
}
 

[轉]數組中只出現一次的兩個數字